Final answer:
To prepare 10 L of a 3 M NaCl solution from a 6 M solution, you need 30 moles of NaCl. Mix 5 liters of the 6 M solution with 5 liters of water to achieve the desired concentration.
Step-by-step explanation:
To prepare 10 L of a 3 M NaCl solution starting from a 6 M NaCl solution, you first need to calculate how many moles of NaCl are present in the final solution. Since molarity (M) is moles of solute per liter of solution, for a 3 M solution, you have 3 moles of NaCl per liter. Therefore, in 10 liters, there will be 30 moles of NaCl (3 moles/L x 10 L).
To obtain 30 moles of NaCl from a 6 M solution, you will need to take a volume that contains exactly 30 moles. As such, you would need 5 liters of the 6 M NaCl solution (30 moles ÷ 6 moles/L). To dilute this to a 3 M solution, you will need to add water to reach a total volume of 10 liters.
Thus, since you are starting with 5 liters of a 6 M solution, you will need to add 5 liters of water to reach 10 liters of a 3 M solution (10 L final volume - 5 L initial volume).
When you are preparing solutions, remember that the volume of solute and solvent together will give you the total volume of the solution. In this scenario, 5 liters of a 6 M NaCl solution mixed with 5 liters of water will give you 10 liters of a 3 M NaCl solution, as dilution involves adding solvent which decreases the concentration of